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Variants and anomalies of the genitourinary organs
Last reviewed: 04.07.2025
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Among the developmental disorders of the kidneys, there are anomalies caused by quantity. There are an additional kidney, which is formed on one side and lies below the normal kidney. Double kidney (ren duplex), which occurs when the primary kidney rudiment on one side divides into two equal parts, rarely - the absence of one kidney (agenesia renis). Anomalies of the kidneys can be associated with their unusual position. The kidney can be located in the area of its embryonic rudiment - kidney dystopia (dystopia renis) or in the pelvic cavity. Anomalies of the kidneys by shape are possible. When the lower or upper ends of the kidneys fuse, a horseshoe-shaped kidney (ren arcuata) is formed. In the case of fusion of both lower ends of the right and left kidneys and both upper ends, a ring-shaped kidney (ren anularis) is formed.
When the development of the tubules and glomerular capsules is disrupted and they remain in the kidney in the form of isolated vesicles, a congenital cystic kidney develops.
Ureteral anomalies are observed in the form of its duplication on both sides or on one side. A split ureter (ureter rissus) is found in its cranial or, less commonly, caudal section. Sometimes narrowing or widening occurs, as well as protrusions of the ureter wall - ureteral diverticulum.
During the development of the urinary bladder, a protrusion of its wall may appear. Rarely, there is underdevelopment of the wall (its splitting), which is combined with non-union of the pubic bones - ectopia of the urinary bladder (ectopia vesicae urinariae).
Anomalies of the internal genital organs
Anomalies and variants of development of internal male and female reproductive organs arise as a result of their complex transformations during embryogenesis.
Among the anomalies of the gonads, it is necessary to note the underdevelopment of one testicle or its absence (monorchism); with a delay in the descent of the testicles in the small pelvis or in the inguinal canal, bilateral cryptorchidism occurs. The vaginal process of the peritoneum may be unfused, then it communicates with the peritoneal cavity and a loop of the small intestine can protrude into the resulting pocket. Sometimes the testicle is delayed in the process of descent, which leads to its unusual location (ectopia testis). In this case, the testicle can be in the abdominal cavity, either under the skin of the perineum, or under the skin in the area of the outer ring of the femoral canal.
During the development of the ovaries, there are also cases of their abnormal displacement (ectopia ovanorum). One or both ovaries are either located at the deep inguinal ring or pass through the inguinal canal and lie under the skin of the labia majora. In 4% of cases, an additional ovary (ovarium accessorium) is found. Rarely, there is congenital underdevelopment of one, and sometimes both ovaries. Very rarely, there is an absence of the fallopian tubes, as well as closure of their abdominal or uterine opening.
If the distal ends of the right and left paramesonephric ducts do not fuse properly, a bicornuate uterus (uterus bicbrnus) develops, and if there is no union at all, a double uterus and double vagina (a rare anomaly) develop. If the development of the paramesonephric duct is delayed, an asymmetrical or unicornuate uterus develops on one side. Often, the uterus seems to stop developing. Such a uterus is called infantile.
[ Anomalies of the external genitalia
An anomaly in the development of the male external genitalia is hypospadias - incomplete closure of the urethra from below. The male urethra remains below in the form of a slit of greater or lesser length. If the male urethra is split at the top, then its upper split occurs - epispadias. This anomaly can be combined with non-fusion of the anterior abdominal wall and an open bladder in front (ectopia of the bladder). Sometimes the opening of the foreskin does not exceed the diameter of the male urethra in size and the head of the penis cannot exit through such an opening. This condition is called phimosis.
Rare anomalies in the development of the genitals include so-called hermaphroditism (bisexuality). A distinction is made between true and false hermaphroditism. True hermaphroditism is very rare and is characterized by the presence of testicles and ovaries in the same person with either a male or female type of genital structure. So-called false hermaphroditism is more common. In these cases, the gonads belong to one sex, and the external genitals correspond in their characteristics to the other sex. The secondary sexual characteristics resemble those of the opposite sex or are, so to speak, intermediate. A distinction is made between male false hermaphroditism, in which the gonad differentiates as a testicle and remains in the abdominal cavity. At the same time, the development of the genital ridges is delayed. They do not grow together, and the genital tubercle develops insignificantly. These formations imitate the genital slit and vagina, and the genital tubercle imitates the clitoris. In female pseudohermaphroditism, the sex glands differentiate and develop as ovaries. They descend into the thickness of the genital ridges, which come so close to each other that they resemble a scrotum. The terminal part of the urogenital sinus remains very narrow and the vagina opens into the urogenital sinus, so that the vaginal opening becomes barely noticeable. The genital tubercle grows significantly and imitates the penis. The secondary sexual characteristics acquire a male appearance.